December 1 marked the observance of World AIDS Day, a day set aside to focus on treatment of people infected with HIV and AIDS. A growing number of these victims are women.

There was a time when HIV and aids were considered mysterious diseases, their causes unknown. Today the search is on for the origins of the latest outbreak of Ebola in Uganda, the SARS epidemic in Vietnam, or the anthrax contamination in Washington D.C.

These are all challenges for some of the world's most talented scientists. Jeff Swicord has the story of these disease detectives.

TV report transcript

They are called the "disease detectives," the officers of the Epidemic Intelligence Service at the Centers for Disease Control in Atlanta Georgia (EIS): an unusual group of epidemiologists who often find themselves in unfamiliar places, looking for clues to the world's most mysterious disease outbreaks.

Douglas Hamilton is the director of the EIS.

DOUGLAS HAMILTON"We are often faced with situations where there is a disease problem, an outbreak where you don't know what the source is. Or you may know what the source is, but you don't know what the problem is and how it is being transmitted. And, our folks go in and gather the information necessary to try and answer the questions of who is at risk for this disease, how can we prevent this from spreading, and how can we stop the outbreak. And it really is a detective kind of process where you gather bits of information, there is deductive reasoning, and you come up with a proposed plan."

All EIS officers have completed a doctoral degree in fields such as medicine, veterinary studies, and biology. They serve a two-year training fellowship and then most go on to careers in public health. Some move on to work for local health services across the country and others become staff members at EIS. According to Doug Hamilton it takes a special person to become an EIS officer.

DOUGLAS HAMILTON"We look for a couple of things. We look for someone who is really driven to find the answer to an unknown problem. Someone who really wants to tease out the puzzle or figure out what is going on. We also look for people who work well in teams. As an agency we provide assistance to other agencies and we are always on a team. We are not the leaders of the team but we are part of a team. So I have to have people that work well in that environment."

The work environment is not always optimal for scientific research. EIS teams often find themselves in remote small villages where there is no electricity or running water. Staff epidemiologist Joel Montgomery was deployed to a nepovirus outbreak in Malaysia and Singapore, a virus that can cause a host of neurological and pulmonary problems in humans. He teamed up with local health professionals to try to find how the virus was being transmitted to people. After an exhaustive investigation they surmised the virus was being carried by bats.

JOEL MONTGOMERY
"In Malaysia and Singapore there was an intermediate host, we had the bats actually foraging in these fruit. trees above pig pens. They would forage on apples or whatever and they would drop partially eaten fruit into the pigpens and the pigs would get infected and they acted as an amplifying or intermediate host. And they actually transmitted Nipah virus on to humans. And the cases in Malaysia and Singapore were due to pig exposure, not direct exposure to bats."

Investigations are not without their dangers. EIS officers were also deployed to the world's largest Ebola outbreak in Uganda. Out of 426 cases half resulted in death. Ebola is a horrible disease where its victims often die of massive uncontrollable hemorrhaging. It is also very contagious requiring health care workers to wear protective clothing and follow strict procedures to protect themselves from infection. But as EIS officer Scott Harper points out, deadly mistakes were made.

SCOTT HARPER"It is very easy with this virus to pick it up with a patient on a glove for instance and then all it would take would be to rub your own eye. Or to touch your own mouth to self infect. And so even with all the precautions in place -- the barrier precautions and head coverings and gowns and everything else and gloves etcetera -- at four o'clock in the morning if you get a call that a patient is basically bleeding all over the room, that patient is one of your colleagues, a nurse who might have been infected."

The work can be emotionally draining as well. Some of Scott Harper's patients were children the same age as his.

SCOTT HARPER
"We had this huge boundary between them where we could hardly touch them. We were completely gowned and gloved and had all of these barrier precautions in place. And kind of looked like space men and it must have terrifying for them. But to try to get that message across that we were trying to do all that we could for them, and that we really cared for them was a big challenge."

Challenges aside, most EIS officers think they have the most interesting jobs in the world.

DOUGLAS HAMILTON"When interviewed for this job many years ago, one of the things that impressed me was when I talked to one of our current officers, he said to me that, 'the thing I like about this job is it is the first job that I have had where I look forward to coming to work in the morning.' That really impressed me and I think that is true for a lot of people who go through this."